Finishing apparatuses are used for finishing workpieces, for example crankshafts or camshafts. Bearing surfaces of said workpieces that are rotationally symmetrical in the circumferential direction are finished by the workpiece being driven in rotation about an axis of rotation. At the same time, an oscillatory movement in the direction parallel to the axis of rotation takes place between the finishing tool (for example a finishing stone or a finishing belt) and the workpiece to be finished. A cross-grinding structure that is characteristic of the finishing process is produced by finishing a workpiece.
When being machined, a workpiece is arranged in a machining position. In this machining position, the workpiece is clamped in a workpiece-receiving device. Said device usually comprises clamping elements which, when viewed along the workpiece axis, are arranged on opposite sides. For example, conical tips can engage in corresponding recesses which are provided in the end faces of the workpiece.
In order to convey the workpiece between a working position and a loading/unloading position, a workpiece-conveying device is provided. Workpieces to be finished are provided in the loading/unloading position, and are then moved into the working position by means of the workpiece-conveying device. The workpiece is transferred from the working position into the machining position by means of the above-described workpiece-receiving device, where it is finished. The workpiece is then moved back into the working position by releasing the workpiece-receiving device and from there it is moved back into the loading/unloading position by means of the workpiece-conveying device.
The change in position of the workpiece when changing between the working position and the machining position is relatively small and corresponds to an offset of a few millimeters or centimeters between the workpiece axis of the workpiece supported on the support device and a clamping axis of the workpiece-receiving device.
Finishing apparatuses comprising workpiece-conveying devices, which comprise a workpiece holder having a support device for supporting a workpiece, are known from prior uses of the applicant. In the known workpiece-conveying devices, the workpiece holder is moved between the loading/unloading position and the working position along a multi-step conveying path. For example, a workpiece to be finished is moved from the loading/unloading position into the working position by the support device of the workpiece holder first being moved along a first conveying path until the support device, together with the workpiece, is positioned below the working position. From this position, the support device is moved upwards together with the workpiece to be finished until the workpiece holder has reached the working position. From said working position, the workpiece is clamped by the workpiece-receiving device. The workpiece holder is then removed from the clamped workpiece by the workpiece holder first being lowered along the above-mentioned second conveying path and from there being moved back into the loading/unloading position along the first conveying path.
The above-described, multi-step conveying path is also required to convey the workpiece from the working position into the unloading position.